1. Field of the Invention
This invention relates to remote shutter release apparatus and, more, particularly, it concerns a synchronizing device for sequentially activating a pair of cameras in a manner providing simultaneous separate exposures.
2. Description of the Invention
In many photographic applications, it is desirable to have an instant photograph bearing the positive image corresponding exactly to the negative image recorded on roll type film in a conventional camera, for example. Such a positive instant photograph serves as an instant proof for a photograph to be developed later from the exposed negative film. In order for the instant photograph to serve as a true proof or fully accurate duplifcation, however, of the exposure image stored on the negative film, the actual exposures of the instant film and negative film must be simultaneous and also of the same image light.
One approach to providing such simultaneous exposures on instant film and negative film is to use a camera designed especially for that purpose and in which both types of film are present and light from a single exposure lens and shutter arrangement is split so as to simultaneously expose both types of film. Another approach involves the use of a specialty camera which carries both instant and negative type film, but which has light from two separate exposure lenses travel along separate paths to different film planes.
Although the two above-described approaches may provide for essentially duplicate images on instant and negative type film, they require the use of special cameras designed to house and simultaneously expose two types of film.
Yet another approach to producing simultaneous exposures on instant picture and negative film is known as dual camera photography and entails mounting separate cameras adjacent one another with one camera carrying instant picture film and the other housing conventional roll type negative film.
As described in U.S. Pat. No. 4,488,794 issued to Dolgow et al on Dec. 18, 1984 two like cameras are mounted one on top of the other with the lower camera inverted relative to the upper camera and with the camera back of the upper camera carrying the conventional negative type roll film, while the camera back of the lower camera supports instant positive film. Shutter actuation of the cameras is synchronized mechanically by an idler gear placed between the two cameras in a position to operatively engage with a shutter cocking gear of each camera. The idler gear assures that when the cocking gear of one of the cameras is cocked or released, this motion is transmitted to the cocking gear of the other camera. Each of the cameras is actuated by a respective actuator cable driven by a common, manually operated, actuating plunger.
Such an arrangement of separate cameras mounted adjacent one another and having mechanical shutter synchronization, as described in the above-mentioned U.S. Pat. No. 4,488,794, is facilitated by the use of two cameras of the same model, and, in particular, two Mamiya-Sekor Model RB67 cameras. In order to use two cameras of different models and still have the shutter actuation mechanically synchronized, more complex mounting and synchronizing mechanisms may be required. Further, depending on the various models of cameras combined, different mounting and synchronizing mechanisms dedicated to particular camera combinations may be required.
Moreover, different camera models and individual cameras of even the same model have different lag times between camera actuation, i.e. depression of the shutter release button, and shutter actuation. As such, simply synchronizing camera actuation of two cameras does not necessarily synchronize the actual exposures of the two cameras. While published figures of the time lag between camera actuation and shutter opening are available for different camera models, the true opening time varies from camera to camera due to manufacturing tolerances. This is evidenced by recent developments in computer controlled factory calibration systems which adjust, for example, the control constants in individual camera exposure control programming to compensate in part for variations in shutter operation.
It is common practice in studio photography to use a single burst of flash illumination from one or more flash or strobe units to create an exposure. As such, light from one or more ganged flash sources can be used to provide duplicate exposures in separate cameras provided that the shutters of the cameras are both open to receive the flash illumination reflected from the subject. Having both shutters open simultaneously presents a problem, however, for the above-mentioned reason that the timing of actual shutter opening of cameras of the same model type, much less cameras of different models, varies from camera to camera.
In addition, a photographer may choose to use one of the cameras separate from the other or may want to replace one of the cameras with another camera. Hence, a lengthy assembly and disassembly process required by complex or multiple camera mounting and mechanical synchronizing systems is undesirable.
In light of the foregoing, there is a need for a versatile synchronizing device for synchronizing the shutter opening of two cameras of the same or different models in a manner providing for essentially duplicate exposures by a single burst of flash illumination.